scholarly journals Dynamic holdup in a countercurrent gas - flowing solids - packed bed contactors

2004 ◽  
Vol 69 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Nikola Nikacevic ◽  
Aleksandar Dudukovic ◽  
Zlatica Predojevic
Keyword(s):  
Experimental Data ◽  
Packed Bed ◽  
Experimental Measurements ◽  
Actual System ◽  
Operational Conditions ◽  
Wide Range ◽  
Dynamic Holdup

Equations for the prediction of the holdup of dynamic solids in countercurrent gas ? flowing solids ? packed bed contactors are presented in this paper. The correlations do not require the use of parameters that need to be determined by experimental measurements in the actual system of interest. They could be used for a wide range of operational conditions different packing types and a variety of flowing solids materials. The equations are compared with all available experimental data from the literature.

scholarly journals Mathematical modelling of the residence time distribution of CO2 tracer in a three-phase micro-packed bed reactor: An experimental analysis

2021 ◽  
Vol 10 (9) ◽  
pp. e23210917425
Author(s):  
Jornandes Marcelo da Silva ◽  
Vitória da Fonseca Dias ◽  
Jornandes Dias da Silva
Keyword(s):  
Experimental Data ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Adsorption Process ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Experimental Measurements ◽  
Three Phase ◽  
The Mathematical Model

This study reports the residence time distribution (RTD) using CO2 as tracer in Three-phase micro-packed bed (TP-mPB) reactor. Experimental measurements were obtained at the inlet and at the outlet from TP-mPB reactor using the injection of small amount (3%) of CO2 tracer inside the sweep gas current. The dynamic model characterizes a diffusion-adsorption process of CO2 tracer in terms of mass transfer phenomena (external and internal). The mathematical model was validated against a set of experimental data where simulated results of CO2 tracer adequately matched the experimental measures at the outlet of the micro-packed bed.

scholarly journals Validation of Actuator Line and Vortex Models Using Normal Forces Measurements of a Straight-Bladed Vertical Axis Wind Turbine

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 511
Author(s):  
Victor Mendoza ◽  
Anders Goude
Keyword(s):  
Experimental Data ◽  
Vertical Axis ◽  
Slight Improvement ◽  
Vertical Axis Wind Turbine ◽  
Operational Conditions ◽  
Vortex Model ◽  
Normal Forces ◽  
The North ◽  
Vertical Axis Wind Turbines ◽  
Wide Range

Vertical Axis Wind Turbines (VAWTs) are characterized by complex and unsteady flow patterns resulting in considerable challenges for both numerical simulations and measurements describing the phenomena involved. In this study, a 3D Actuator Line Model (ALM) is compared to a 2D and a 3D Vortex Model, and they are validated using the normal forces measurements on a blade of an operating 12 kW VAWT, which is located in an open site in the north of Uppsala, Sweden. First, the coefficient power ( C P ) curve of the device has been simulated and compared against the experimental one. Then, a wide range of operational conditions for different tip speed ratios (TSRs), with λ = 1.84, 2.55, 3.06, 3.44, 4.09 and 4.57 were investigated. The results showed descent agreement with the experimental data for both models in terms of the trend and magnitudes. On one side, a slight improvement for representing the normal forces was achieved by the ALM, while the vortex code performs better in the simulation of the C P curve. Similarities and discrepancies between numerical and experimental results are discussed.

The course of hematocrit value along the length of a dialyzer’s fiber: Hemoconcentration modeling and validation methods

2019 ◽  
Vol 42 (9) ◽  
pp. 482-489
Author(s):  
Ali Poorkhalil ◽  
Foivos Mouzakis ◽  
Ali Kashefi ◽  
Khosrow Mottaghy
Keyword(s):  
Experimental Data ◽  
Driving Forces ◽  
Semiempirical Model ◽  
Sequential Order ◽  
Filtration Process ◽  
Operational Conditions ◽  
Wide Range ◽  
Hemodynamic Characteristics ◽  
Good Agreement

Objectives:Contemporary therapies for chronic kidney disease patients encompass a wide range of hemodialysis treatments, most of which rely greatly on dialyzers and hemofilters. The filtration process taking place in these devices with respect to the hemodynamic characteristics of the flow, has not yet been fully investigated. This study aims at improving the understanding of hemodynamics in a dialyzer by employing experimental methods and mathematical models.Methods:A semiempirical model has been formulated based on the principles of hemodynamics, considering the dominant phenomena of filtration-backfiltration and the corresponding driving forces. An in vitro hemodialysis circuit was accordingly assembled for experimental data acquisition, and subsequently for model validation. The circuit consisted of two dialyzers arranged in sequential order, in pursuance of increasing the number of sampling points. Fresh, heparinized porcine blood was used throughout the course of this study. Pressure and flow data obtained from in vitro investigations with the hemodialysis circuit were used as an input for the semiempirical model.Findings:The model predicted a substantial divergence in the course of hematocrit value along the length of the hollow fibers, which is corroborated by the experimental data. Particularly in certain operational conditions, hematocrit rose from 25% at the inlet to 65% halfway along the dialyzers’ length, to end at 30% at the outlet.Conclusion:Validation of the model’s predictions with experimental data demonstrated a very good agreement, confirming the model’s accuracy. Potential implementation of the model in clinical practice in the future might contribute greatly to an improved hemodialysis experience.

scholarly journals Density estimation for waste cooking oil biodiesel

2019 ◽  
Vol 17 (6) ◽  
pp. 21
Author(s):  
Xuân Nguyễn Thị Thanh
Keyword(s):  
Experimental Data ◽  
Predictive Models ◽  
Acid Methyl Ester ◽  
Waste Cooking Oil ◽  
High Accuracy ◽  
Experimental Measurements ◽  
Calculated Density ◽  
Cooking Oil ◽  
Acid Methyl ◽  
Wide Range

This paper focuses on the biodiesel density predictive models and examines the accuracy of the HCC methodology which bases on Rackett equation modified by Spencer and Danner to estimate the density of waste cooking oil (WCO) biodiesel in a wide range of temperature based on its fatty acid methyl ester components. The calculated results are compared with experimental measurements for the density aiming to validate the chosen method. The analysis results obtained show that this method does not, in all cases, yield high accuracy even though its use is simple. Particularly, in case of the biodiesel derived from waste cooking oil (WCO), this method is not accurate enough to predict its density with the deviations between experimental data and calculated density getting relatively high, around 3.4%

LIQUIDUS THERMO-BAROMETER FOR THE MODELING OF MAGNETITE — MELT EQUILIBRIUM

2018 ◽  
pp. 71-80
Author(s):  
N. S. Aryaeva ◽  
E. V. Koptev-Dvornikov ◽  
D. A. Bychkov
Keyword(s):  
Experimental Data ◽  
Liquidus Temperature ◽  
Vertical Structure ◽  
Maximum Error ◽  
Silicate Melt ◽  
System Of Equations ◽  
Wide Range ◽  
Basaltic Melts ◽  
Multidimensional Statistics

A system of equations of thermobarometer for magnetite-silicate melt equilibrium was obtained by method of multidimensional statistics of 93 experimental data of a magnetite solubility in basaltic melts. Equations reproduce experimental data in a wide range of basalt compositions, temperatures and pressures with small errors. Verification of thermobarometers showed the maximum error in liquidus temperature reproducing does not exceed ±7 °C. The level of cumulative magnetite appearance in the vertical structure of Tsypringa, Kivakka, Burakovsky intrusions predicted with errors from ±10 to ±50 m.

Theoretical analysis of counter-current absorption of a poorly soluble gas based on the PDE-AD model

1986 ◽  
Vol 51 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Gas Phase ◽  
Transfer Functions ◽  
Packed Bed ◽  
Packed Bed Column ◽  
Interfacial Transport ◽  
Gaseous Component ◽  
Poorly Soluble ◽  
Counter Current

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.

scholarly journals Soft-drop grooming for hadronic event shapes

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Jeremy Baron ◽  
Daniel Reichelt ◽  
Steffen Schumann ◽  
Niklas Schwanemann ◽  
Vincent Theeuwes
Keyword(s):  
Event Generator ◽  
Experimental Measurements ◽  
Event Shape ◽  
Matrix Elements ◽  
Underlying Event ◽  
Hadronic Event ◽  
Wide Range ◽  
Event Shapes ◽  
The Impact ◽  
Perturbative Corrections

Abstract Soft-drop grooming of hadron-collision final states has the potential to significantly reduce the impact of non-perturbative corrections, and in particular the underlying-event contribution. This eventually will enable a more direct comparison of accurate perturbative predictions with experimental measurements. In this study we consider soft-drop groomed dijet event shapes. We derive general results needed to perform the resummation of suitable event-shape variables to next-to-leading logarithmic (NLL) accuracy matched to exact next-to-leading order (NLO) QCD matrix elements. We compile predictions for the transverse-thrust shape accurate to NLO + NLL′ using the implementation of the Caesar formalism in the Sherpa event generator framework. We complement this by state-of-the-art parton- and hadron-level predictions based on NLO QCD matrix elements matched with parton showers. We explore the potential to mitigate non-perturbative corrections for particle-level and track-based measurements of transverse thrust by considering a wide range of soft-drop parameters. We find that soft-drop grooming indeed is very efficient in removing the underlying event. This motivates future experimental measurements to be compared to precise QCD predictions and employed to constrain non-perturbative models in Monte-Carlo simulations.

scholarly journals Experimental analysis and ANN prediction on performances of finned oval-tube heat exchanger under different air inlet angles with limited experimental data

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 968-980
Author(s):  
Xueping Du ◽  
Zhijie Chen ◽  
Qi Meng ◽  
Yang Song
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Correlation Equation ◽  
Tube Heat Exchanger ◽  
Flow Friction ◽  
Air Inlet ◽  
Comparison Results ◽  
Wide Range ◽  
Oval Tube

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

scholarly journals Modelling the Inflation and Elastic Instabilities of Rubber-Like Spherical and Cylindrical Shells Using a New Generalised Neo-Hookean Strain Energy Function

2021 ◽  
Author(s):  
Afshin Anssari-Benam ◽  
Andrea Bucchi ◽  
Giuseppe Saccomandi
Keyword(s):  
Experimental Data ◽  
Energy Function ◽  
Limit Point ◽  
Strain Energy ◽  
Cylindrical Shells ◽  
Strain Energy Function ◽  
Model Parameters ◽  
Wide Range ◽  
Cylindrical Tubes ◽  
Gent Model

AbstractThe application of a newly proposed generalised neo-Hookean strain energy function to the inflation of incompressible rubber-like spherical and cylindrical shells is demonstrated in this paper. The pressure ($P$ P ) – inflation ($\lambda $ λ or $v$ v ) relationships are derived and presented for four shells: thin- and thick-walled spherical balloons, and thin- and thick-walled cylindrical tubes. Characteristics of the inflation curves predicted by the model for the four considered shells are analysed and the critical values of the model parameters for exhibiting the limit-point instability are established. The application of the model to extant experimental datasets procured from studies across 19th to 21st century will be demonstrated, showing favourable agreement between the model and the experimental data. The capability of the model to capture the two characteristic instability phenomena in the inflation of rubber-like materials, namely the limit-point and inflation-jump instabilities, will be made evident from both the theoretical analysis and curve-fitting approaches presented in this study. A comparison with the predictions of the Gent model for the considered data is also demonstrated and is shown that our presented model provides improved fits. Given the simplicity of the model, its ability to fit a wide range of experimental data and capture both limit-point and inflation-jump instabilities, we propose the application of our model to the inflation of rubber-like materials.

The Petrogenetic Model, an Extension of Bowen's Petrogenetic Grid

1962 ◽  
Vol 99 (6) ◽  
pp. 558-569 ◽  
Author(s):  
Peter J. Wyllie
Keyword(s):  
Experimental Data ◽  
Constant Pressure ◽  
Three Dimensional ◽  
Pore Fluid ◽  
Fluid Composition ◽  
Solid Reaction ◽  
Petrogenetic Model ◽  
Wide Range ◽  
Opposite Face ◽  
Reaction Surfaces

AbstractBowen's petrogenetic grid is a PT projection containing univariant curves for decarbonation, dehydration, and solid-solid reactions, with vapour pressure (Pf) equal to total pressure (Ps). Analysis of experimental data in the system MgO–CO2–H2O leads to an expansion of this grid. Three of the important variables in metamorphism when Pf = Ps are P, T, and variation of the pore fluid composition between H2O and CO2. These can be illustrated in a three-dimensional petrogenetic model; one face is a PT plane for reactions occurring with pure H2O, and the opposite face is a similar plane for reactions with pure CO2; these are separated by an axis for pore fluid composition varying between H2O and CO2. Superposition of the PT faces of the model provides the petrogenetic grid. The reactions within the model are represented by divariant surfaces, which may meet along univariant lines. For dissociation reactions, the surfaces curve towards lower temperatures as the proportion of non-reacting volatile increases, and solid-solid reaction surfaces are parallel to the vapour composition axis and perpendicular to the PT axes. The relative temperatures of reactions and the lines of intersections of the surfaces can be illustrated in isobaric sections. Isobaric sections are used to illustrate reactions proceeding at constant pressure with (1) pore fluid composition remaining constant during the reaction, with temperature increasing (2) pore fluid composition changing during the reaction, with temperature increasing, and (3) pore fluid changing composition at constant temperature. The petrogenetic model provides a convenient framework for a wide range of experimental data.

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